MODIFICATION OF PbS NOISE SPECTRA BY RADIATION

Abstract

The noise spectra of PbS photoconductive cells can be modified by optically excited carriers. Detailed wavelength studies at CO2 temperatures have shown that g–r noise can be obtained using light of the 2.4-micron region, and the 1/f form with radiation of the 1.0-micron region. The effect is explained by assuming that minority carrier lifetimes in Kodak Ektron detectors are very short. The 1/f noise is only observed when optical carriers are produced very near the cell surface.